For all that we've learned about Hawai'i's volcanoes during the Hawaiian Volcano Observatory's first 100 years, there are still questions to be answered. James Dwight Dana, one of the first geologists to study Hawaiian volcanoes, called these unknowns "points requiring elucidation" in 1890. Since then, many of Dana's points have been addressed, but some have not, and new questions have arisen from the continuous observation and study of Hawaiian volcanoes. USGS Hawaiian Volcano Observatory scientist Mike Poland will discuss the big issues faced by volcanologists studying Hawaiian volcanoes today, from the source of magma deep within the Earth to predicting eruptions—or determining when an ongoing eruption will end!